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([2a02:810d:4b3f:de9c:642:1aff:fe31:a15c]) by smtp.gmail.com with ESMTPSA id a13-20020a170906684d00b0096f7500502csm9582514ejs.199.2023.06.15.09.39.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Jun 2023 09:39:22 -0700 (PDT) Message-ID: <68cd25de-e767-725e-2e7b-703217230bb0@redhat.com> Date: Thu, 15 Jun 2023 18:39:20 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH drm-next v4 00/14] [RFC] DRM GPUVA Manager & Nouveau VM_BIND UAPI Content-Language: en-US To: Liam.Howlett@oracle.com Cc: airlied@gmail.com, daniel@ffwll.ch, tzimmermann@suse.de, mripard@kernel.org, corbet@lwn.net, christian.koenig@amd.com, bskeggs@redhat.com, matthew.brost@intel.com, boris.brezillon@collabora.com, alexdeucher@gmail.com, ogabbay@kernel.org, bagasdotme@gmail.com, willy@infradead.org, jason@jlekstrand.net, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230606223130.6132-1-dakr@redhat.com> From: Danilo Krummrich Organization: RedHat In-Reply-To: <20230606223130.6132-1-dakr@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/7/23 00:31, Danilo Krummrich wrote: > Maple Tree: > - Maple tree uses the 'unsinged long' type for node entries. While this > works for 64bit, it's incompatible with the DRM GPUVA Manager on 32bit, > since the DRM GPUVA Manager uses the u64 type and so do drivers using it. > While it's questionable whether a 32bit kernel and a > 32bit GPU address > space make any sense, it creates tons of compiler warnings when compiling > for 32bit. Maybe it makes sense to expand the maple tree API to let users > decide which size to pick - other ideas / proposals are welcome. I remember you told me that the filesystem folks had some interest in a 64-bit maple tree for a 32-bit kernel as well. Are there any news or plans for such a feature? For the short term I'd probably add a feature flag to the GPUVA manager, where drivers explicitly need to promise not to pass in addresses exceeding 32-bit on a 32-bit kernel, and if they don't refuse to initialize the GPUVA manager on 32-bit kernels - or something similar...